Conventional cattle feeds such as corn and alfalfa often fail to provide sufficient energy for cattle, especially lactating dairy cattle during periods of heavy milk production. Feed containing a high proportion of corn also has a tendency to depress the milk fat content of the milk produced by such cattle. Fat is an excellent energy source, and it is known that if the proportion of fat in cattle food is increased, lactating dairy cattle produce high milk yields without draining their reserves of body fat and without diminishing the proportion of milk fat in the milk produced.
However, it has been found that if the proportion of fat in the diet of cattle exceeds about 2% of the total feed solids, the feed has toxic effects upon the microorganisms in the rumen of the cattle. It appears that fat reduces the growth rate or even kills certain microorganisms which digest fiber in the cow's rumen, thereby lowering fiber digestibility. This deleterious effect on the cow's rumen is particularly true of unsaturated fats. Although the decreased fiber digestion in the rumen is partially compensated by greater fiber digestion in the lower parts of the alimentary canal, such later fiber digestion produces a blend of different fatty acids than that which is produced by the digestion in the rumen, and the different blend of fatty acids is less suited to the cow's metabolism.
It is known also that triglycerides and free fatty acids can physically coat fibrous or cellulosic material in the rumen and inhibit fermentation of the material by the bacteria. This has an adverse effect on the total digestibility of the diet, and can result in a reduced yield of milk and butter-fat.
There has been a continuing need for new dietary supplements for animal foodstuff which can be fed to ruminant animals without interfering with feed metabolism by rumen microorganisms.
U.S. Pat. Nos. 4,642,317; 4,826,694; 4,853,233; and 4,909,138 describe the incorporation of insoluble fatty acid salts in ruminant feed as a means of increasing the fat content of the feed without deleteriously affecting the ruminant digestion cycle. A feed additive such as fatty acid calcium salt functions as a rumen bypass product, and is subsequently metabolized in the abomasum or small intestine of the ruminant.
Accordingly, it is an object of this invention to provide a fatty acid salt composition which contains little or no free fatty acid or fatty acid glyceride, and which can function as a rumen bypass animal feed supplement and promote a beneficial increase in the dietary fat content of the feed.
It is another object of this invention to provide a particulate fatty acid salt product which consists essentially of calcium salts of a fatty acid mixture, and which is substantially free of glyceride ingredient and odorant impurities.
It is a further object of this invention to provide an animal feed supplement product which comprises a high purity fatty acid calcium salt ingredient, in comb]nation with a biologically active ingredient.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.